About Carabidae
Carabidae, commonly known as ground beetles, vary somewhat in body shape and coloration, but most individuals have a shiny black or metallic appearance, with ridged wing covers called elytra. In some species, especially large members of the subfamily Carabinae, the elytra are fused, which leaves these beetles unable to fly. The species Mormolyce phyllodes is called the violin beetle, named for its unusually shaped elytra. All carabids except the relatively primitive flanged bombardier beetles of the subfamily Paussinae have a groove on their foreleg tibiae that holds a comb of hairs, which the beetles use to clean their antennae. Common habitats for carabids include under tree bark, under logs, and among rocks or sand along the edges of ponds and rivers. Most carabid species are carnivorous, and actively hunt any invertebrate prey they are able to overpower. Some run quickly to catch their prey; tiger beetles of the subfamily Cicindelinae can reach sustained speeds of 9 km/h (5.6 mph). Relative to their body length, tiger beetles are among the fastest land animals on Earth. Unlike most carabids, which are active at night, tiger beetles are diurnal active hunters, and are often brightly colored. They have large eyes and hunt using their sense of sight. Ground beetles in the genus Promecognathus are specialized predators of the cyanide millipedes Harpaphe haydeniana and Xystocheir dissecta. These beetles can counter the hydrogen cyanide that makes these millipedes poisonous to most other carnivores.
